Vitamin K in fish nutrition     

C. KROSSØY  R. WAAGBØ  R. ØRNSRUD 《Aquaculture Nutrition》2011,17(6):585-594

Vitamin K belongs to the lipid soluble vitamins, and occurs naturally as phylloquinone (vitamin K₁) and menaquinone (vitamin K₂). In addition, there is a synthetic provitamin, menadione (vitamin K₃), primarily used as a vitamin K source in animal feed. Menadione is unstable during feed processing and storage and the dietary content may reach critically low levels. Recent publications also question the availability of menadione in feed for salmonids. Vitamin K plays vital roles in blood coagulation and bone mineralization in fish, but the suggested minimum requirement varies considerably depending on the vitamin K source used. Vitamin K deficiency is characterized by mortality, anaemia, increased blood clotting time and histopathological changes in liver and gills. However, one should assess both inherent and supplemented forms of vitamin K in feeds for exact determinations, as relevant novel feed ingredients of plant origin may be sufficient to meet the requirement for vitamin K. The current review gives an overview of the biochemical role of vitamin K, and discusses vitamin K requirement in fish in light of updated literature, with special emphasis on salmonids.  相似文献   

The effect of lactic acid bacteria administration on growth,digestive enzyme activity and gut microbiota in Persian sturgeon (Acipenser persicus) and beluga (Huso huso) fry     

F. ASKARIAN  A. KOUSHA  W. SALMA  E. RINGØ 《Aquaculture Nutrition》2011,17(5):488-497

The aims of this study was to assess the effect of two lactic acid bacteria (LAB), Lactobacillus curvatus and Leuconostoc mesenteroides, originally isolated from gastrointestinal (GI) tract of beluga (Huso huso) and Persian sturgeon (Acipenser persicus), respectively, on growth, survival and digestive enzyme (amylase, lipase and protease) activities and the population level of LAB in the GI tract. The treatments included 10 different groups; control, separate supplements of L. curvatus and Leu. mesenteroides at three different counts [2 × 10⁹, 5 × 10⁹ and 9 × 10⁹ colony forming units (CFU) per gram food] and three combinations of the two LAB (2 × 10⁹ + 2 × 10⁹, 5 × 10⁹ + 5 × 10⁹ and 9 × 10⁹ + 9 × 10⁹ CFU per gram food). The bacteria used in this study were added in lyophilized form to chopped Chironomidae. In the beluga study, highest specific growth rate, survival and improved intestinal enzyme activities were noted in the rearing group fed 9 × 10⁹ L. curvatus per gram food. In Persian sturgeon, the inclusion level of 2 × 10⁹ Leu. mesenteroides had similar positive effect. The ability of LAB to colonize the digestive tract seems to involve host specificity, and our bacteriological results are relevant to initiate future probiotic studies in sturgeons and future directions will be discussed.  相似文献   

Aspects of landscape or nature quality     

Arler  Finn 《Landscape Ecology》2000,15(3):291-302

Landscape or nature quality has become a key concept in relation to nature policy and landscape planning. In the first part of the article it is argued, that these qualities should not be conceived as mere expressions of private or subjective preferences. Even though there may not be any `objective' or `scientific' method dealing with them, they are still values which can be shared, reflected on, and discussed in a reasonable way. The connoisseurs are introduced as experienced persons, who are particularly capable of identifying different kinds of qualities, bridge builders between cognition and evaluation. The second part of the article deals with four central sets of landscape or nature qualities: qualities related to species diversity, qualities related to the `atmospheres' and characters of places, pictorial qualities, and qualities related to narrativity. It is argued that experience of these and similar qualities are an important part of human flourishing, and that they should therefore all have a prominent place in landscape planning.Finn, Arler, M.A. and Ph.D. in Philosophy. Research Fellow, associated with the interdisciplinary research group `Boundaries in the Landscape', sponsored by the Danish Research Councils. Teaches environmental ethics at the Human Ecology course at Aalborg University, Denmark.  相似文献   

Design and Validation of an Assay for Isotope Ratio Mass Spectrometry Analysis of Biologically Relevant Dissolved and Heat-Extracted Organic Carbon with Neutral Potassium Phosphate Buffer     

Damien Finn  Fred Oudyn  Kerrilyn Catton  Ram Dalal 《Communications in Soil Science and Plant Analysis》2016,47(17):2017-2025

Labile soil dissolved organic carbon (DOC) and heat-extracted carbon (HEC) are sensitive indicators of changing soil organic carbon (SOC) stocks. Isotope ratio mass spectrometry (IRMS) is an important tool for studying SOC turnover and soil biological function. Several complications are involved in measuring DOC/HEC, for example salt ionic strength; solution pH; and anionic damage to elemental analyzer-IRMS. We evaluated a method for DOC/HEC analysis with 0.1 M potassium phosphate buffer (PPB). This method was strongly correlated with commonly used carbon (C) extractants for C quantification. Carbon-13 comparisons between DOC/HEC extracted with Milli-Q water and PPB were similar. The δ¹³C (‰) values of particulate OC and DOC were similar, whereas the relationship between humic OC and HEC was soil specific. An incubation experiment demonstrated that DOC/HEC δ¹³C (‰) successfully explained respired microbial carbon dioxide over 90 days. We conclude that this method represents an alternative for DOC/HEC quantification and δ¹³C (‰) analyses.  相似文献   

The effect of plant‐based diet and suboptimal environmental conditions on digestive function and diet‐induced enteropathy in rainbow trout (Oncorhynchus mykiss)          下载免费PDF全文

P. Mosberian‐Tanha  J.W. Schrama  T. Landsverk  L.T. Mydland  M. Øverland 《Aquaculture Nutrition》2018,24(1):112-122

This experiment investigated intestinal enteropathy and digestive function of rainbow trout challenged with soybean meal‐based diet (SBM) at optimal or suboptimal environments created by normal or reduced water flow, respectively. Oxygen level remained above 7 mg L^‐1 for optimal environment and between 4 and 5 mg L^‐1 for suboptimal environment. Triplicate groups of fish (mean body weight 74 g) were fed fishmeal‐based diet (FM) or SBM at optimal environment in period 1 (28 days). In period 2 (42 days), fish were subjected to a change from FM to SBM or remained on the same diet as used in period 1. The fish were also exposed to change from optimal to suboptimal environment or remained under optimal conditions. The fish subjected to change from FM to SBM, regardless of their environment, showed similar degree of enteropathy from day 14. Lipid and starch digestibility was lower in SBM‐fed fish at suboptimal environment compared to fish fed the same diet at optimal environment. Crude protein digestibility, however, was highest in SBM‐fed fish at suboptimal environment throughout period 2. In conclusion, in SBM‐fed rainbow trout, exposure to suboptimal environment did not change the degree of enteropathy; however, lipid and starch digestibility were further reduced.  相似文献   

High salinity tolerance in eggs and fry of a brackish Esox lucius population     

A. T. JØRGENSEN  B. W. HANSEN  B. VISMANN  L. JACOBSEN  C. SKOV  S. BERG  D. BEKKEVOLD 《Fisheries Management and Ecology》2010,17(6):554-560

Abstract Knowledge on the biology and physiology of pike, Esox lucius L., populations inhabiting saline environments is scarce. An experimental setup was used to examine egg development and fry behaviour and growth under varying salinity levels in a brackish‐water pike population from the western Baltic Sea. Eggs and fry developed at 8.5 psu, which is higher than hitherto reported for other populations. Fry exhibited stress behaviour and reduced growth when subjected to salinities above 13 psu. This indicates that early life stages of E. lucius tolerate ambient salinity conditions equivalent to the natural environment in its nursery area in the Stege Nor lagoon. The population should therefore not be dependent on access to freshwater environments during spawning. However, the results also suggest that the population’s natural environment is on the margin of its physiological capacity. The results have significance for management of brackish‐water E. lucius populations, e.g. in relation to stocking strategies.  相似文献   

Pea and wheat starch possess different processing characteristics and affect physical quality and viscosity of extruded feed for Atlantic salmon     

M. SØRENSEN  T. MORKEN  M. KOSANOVIC  M. ØVERLAND 《Aquaculture Nutrition》2011,17(2):e326-e336

The aim of the study was to investigate the effect of starch source, retention time in the preconditioner and screw speed (RPM) on physical quality of extruded fish feeds. The experiment was arranged in a three by two by two factorial design using three carbohydrate sources [wheat starch (WS), pea starch (PS) or a combination (WS_PS)], two retention times in the preconditioner [long (120 s) or short (62 s)] and two RPM in the extruder [high (300) or low (220)]. Physical quality was assessed by hardness, diameter, expansion ratio, Holmen durability (HDI), DORIS value (DV), oil absorption capacity, oil leakage and pasting viscosity. The results showed that retention time in the preconditioner only affected HDI and oil leakage. Long retention time improved HDI but caused a greater leakage. Changing screw speed from 220 to 300 RPM gave a greater expansion ratio, improved HDI and oil absorption. PS resulted in higher pasting viscosity, HDI and DV, but a generally lower hardness than WS. To conclude, PS and WS have different processing characteristics, and the conditions need to be adjusted according to the starch source used when producing extruded fish feed.  相似文献   

Successive bulk propagation of juvenile plants from full-sib families of Norway spruce     

Øystein Johnsen 《Forest Ecology and Management》1985,11(4):271-282

The results of bulk propagation of Norway spruce for one year are presented. The number of cuttings produced per seedling ranged from 21 to 38 between different families, with a large within-family variation. No clear relationship between family field performance and production of cuttings could be seen. Established cuttings produced more propagules per plant than seedlings in the first propagation. Misting gave about 92% rooting, with no significant differences between different rooting media used. A bulk propagation programme is proposed with a potential production of about 1000–1500 plants per germinated seed within 3 years of sowing.  相似文献   

Economic values for lean meat and fat efficiency in Norwegian Landrace nucleus pig population     

Kristine Hov Martinsen  Dan Olsen  Jørgen Ødegård  Theodorus Meuwissen 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2016,66(3):145-151

A profit function was developed to estimate economic values for new efficiency traits for fattening pigs in Norwegian Landrace. These traits were lean meat efficiency (LME) and fat efficiency (FE). LME and FE described how much feed the animal used to produce 1?kg lean meat and fat as a deviation from the mean. Both traits were derived from analysing total feed consumption in a random regression model which included lean meat and fat content of the carcass (FC) as random covariates. In addition, economic values and breeding values were calculated for days from 40 to 100/120?kg live weight (DAYS), lean meat percentage (LMP) and FC. To compare LME and FE with total feed intake (FI), two indexes were constructed. One index included LME, FE, DAYS, LMP and FC and was referred to as breeding goal A and one index included FI, LMP and DAYS and was referred to as breeding goal B. The standardized economic values for LME and FE were 8.9 and 2.9 EUR/σ_a, respectively. There was a larger variation in the index for breeding goal A (SD?=?5.65) than B (SD?=?3.97). The results suggested that the two efficiency traits had an economic importance in pork production and that there was a potential for increased genetic gain in profit by using breeding goal A compared to breeding goal B.  相似文献   

Methylation of tRNAAsp by the DNA methyltransferase homolog Dnmt2   总被引：1，自引：0，他引：1  

Goll MG  Kirpekar F  Maggert KA  Yoder JA  Hsieh CL  Zhang X  Golic KG  Jacobsen SE  Bestor TH 《Science (New York, N.Y.)》2006,311(5759):395-398

The sequence and the structure of DNA methyltransferase-2 (Dnmt2) bear close affinities to authentic DNA cytosine methyltransferases. A combined genetic and biochemical approach revealed that human DNMT2 did not methylate DNA but instead methylated a small RNA; mass spectrometry showed that this RNA is aspartic acid transfer RNA (tRNA(Asp)) and that DNMT2 specifically methylated cytosine 38 in the anticodon loop. The function of DNMT2 is highly conserved, and human DNMT2 protein restored methylation in vitro to tRNA(Asp) from Dnmt2-deficient strains of mouse, Arabidopsis thaliana, and Drosophila melanogaster in a manner that was dependent on preexisting patterns of modified nucleosides. Indirect sequence recognition is also a feature of eukaryotic DNA methyltransferases, which may have arisen from a Dnmt2-like RNA methyltransferase.  相似文献